To reiterate what has been said before: As long as the cambium - the layer right under the bark - is still green when you scratch lightly on a twig, the tree is alive. You may have some tip die-back to trim off (if you can reach it), but the tree itself should be fine. Most trees have auxilliary buds; they will grow and leaf out soon. Wait until the leaves are clearly growing before you do any trimming, and be careful of the emerging leaves. Resist the temptation to clean off the old leaves, unless you did it straight away - you might damage the emerging buds. Water the tree well, but don't drown it, as few trees like standing in water. And don't fertilize until the tree has almost all the leaves out, and then lightly with a slow release fertilizer. In other words, wait until at least the end of May before you decide your tree is dead. Most of the trees that people grow in their yards evolved to cope with late frosts. While this freeze was very late and very severe, few trees will completely die from it. They may not be as beautiful this summer as in past years, but they will live. By the end of summer, you probably won't even know there was a problem. If a tree was very young or not doing well for one reason or another, then it might be dead. However, most of the seedlings I had in pots are doing fine. I lost one or two, but I normally do over a winter anyway.

Thank you for your quick responses. The trees were here and appeared to be mature, or nearly so, when I moved here 8 yrs ago, 2002, (south central PA). They were probably planted by landscapers when the house was built in 1998; I do not have any information on their species, origins, age, planting or soil conditions or care from 1998 to 2002. As I mentioned, they appeared to be in good health until the past couple of years. The winters here are cold and snowy/icy - last winter we had epic snow and the winter before was nearly all ice storms; the summers are sometimes dry sometimes wet sometimes both, typically hot and humid; this summer was quite dry for a while then wet. The trees are on a slope along with other ornamental shrubs and ground cover, and they get a lot of sun. There is no mulching around their trunks. I have done nothing to them except keep them watered during draught times, and this spring some large dead branches were removed. It is night time right now, so I could take some pictures during the day and also look more carefully at the leaves and areas you mentioned. Again thanks.

Congrats Linda! That's so great! Maybe, it does have something to do with your milder winter? Either way...enjoy the extra blooms and your milder winter as well.

You should be getting flowers by now. Citrus often flowers in the pot at the nursery, begore planting. Perhaps they are getting too much nitrogen. Some of my citrus have not made flower buds yet this year, but I am expecting them to bud soon. Most of my citrus just budded this month. The Meyer lemons kind of always bloom. Last year most of my citrus started in January. Don't know why they are late this year. I wish I could help, but I have no idea why your trees haven't budded at this age. They definitely should. I'm assuming they are grafted trees. Make sure no branches are below the graft. I have to prune several times a year to remove sprouts below the graft (by rubbing them off by hand while they are still tender).